<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>Test
  <div>b</div>
</div>
</body>
<script>
  document.onmousemove = function(){
       console.log(event.target)
  }
       // function test(){
       //   console.log(event.target);
       // }
</script>
</html>